Abstract/Summary

The sedimentary processes and evolution of a presumably old but still relatively recent active canyon-fed sandy turbidite system on the Norwegian continental margin, the Andoya Canyon - Lofoten Basin Channel system, were studied using high-resolution seismic, deep-towed side-scan sonar records and cores (gravity and vibro cores). The canyon has a length of about 40 km and represents a continental slope incision of up to 1100 m. From the canyon mouth, a deep-sea channel up to 30 m deep and 3 km wide continues for approximately 200 km into the deepest part of the Lofoten Basin. The most recent activity of this system was deposition of coarse-grained sediments from turbidity currents as indicated by sediment waves on the canyon floor, thin sand layers within the levees and a sandy lobe at the channel mouth. From this modern system we suggest that there are a number of features that could be of relevance for hydrocarbon exploration of deep-water turbidite systems: a) this canyon-fed system probably received sand from piracy of shelf sediments and/or canyon wall erosion, b) the sandy deposits are located in the deepest part of the basin, about 200 km outside the canyon mouth, c) the sandy lobe is connected to the source area by a straight channel with poorly developed mud-rich levees, d) the sandy deposits have a sheet-like or tabular geometry, e) post-depositional deformation of the sand could be widespread suggesting rapid sand deposition. Thus, modern, canyon-fed sandy turbidite systems provide additional data relevant for future hydrocarbon prospecting in deep-water areas.